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Paroxysmal nocturnal hemoglobinuria (PNH)

Definition

Paroxysmal nocturnal hemoglobinuria is a rare disease in which red blood cells break down earlier than normal.

Alternative Names

PNH

Causes, incidence, and risk factors

Persons with this disease have blood cells that are missing a gene called PIG-A. This gene allows a substance called glycosyl-phosphatidylinositol (GPI) to help certain proteins stick to cells.

Without PIG-A, important proteins cannot connect to the cell surface and protect the cell from substances in the blood called complement. As a result, red blood cells break down too early. The red cells leak hemoglobin into the blood, which can pass into the urine. This can happen at any time, but is more likely to occur during the night or early morning.

The disease can affect people of any age. It may lead to aplastic anemia , myelodysplastic syndrome, or acute myelogenous leukemia .

Risk factors, except for prior aplastic anemia, are not known.

Symptoms

Signs and tests

Red and white blood cell counts and platelet counts may be low.

Red or brown urine signals the breakdown of red blood cells and that hemoglobin is being released into the body's circulation and eventually into the urine.

Tests that may be done to diagnose this condition may include:

Treatment

Steroids or other drugs that suppress the immune system may help slow the break down of red blood cells. Blood transfusions may be needed. Supplemental iron and folic acid are provided. Blood thinners may also be needed to prevent clot formation.

Soliris (eculizumab) is a drug used to treat PNH. It blocks the breakdown of red blood cells.

Bone marrow transplantation can cure this disease.

All patients with PNH should receive vaccinations against certain types of bacteria to prevent infection. Ask your doctor which ones are right for you.

Support Groups

Expectations (prognosis)

The outcome varies. Most people survive greater than 10 years after their diagnosis. Death can result from complications such as blood clot formation (thrombosis) or bleeding.

In rare cases, the abnormal cells may decrease over time.

Complications

Calling your health care provider

Call your health care provider if you find blood in your urine, if symptoms worsen or do not improve with treatment or if new symptoms develop.

Prevention

There is no known way to prevent this disorder.

References

US Food and Drug Administration. . Rockville, MD: National Press Office; March 16, 2007. Release P07-47.

Schwartz RS. Autoimmune and intravascular hemolytic anemias. In: Goldman L, Ausiello D, eds. . 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 164.

Encyclopedia content is provided as information only and not intended to replace the advice and instruction from your personal physician.